Pain after fingering

Okay, so my girlfriend had done nothing at all when we started going out. Eventually she decided she wanted to try things, so I fingered her. There have been problems though.

Incident #1:
Everything was fine until afterwards, when she said she experienced an "empty" pain in her abdomen, and feeling sick. I think it's a similar pain to when a guy gets kicked in his jewels. I believe this was caused because I was a little too rough on the clitoris.

I fingered her once more with no consequences before incident #2 happened:
So everything was going fine again. I had eased in going deeper than I had done before and she didn't feel any pain so I took that as a sign that it was fine. Eventually, as she was well lubricated, I slipped in another finger. I didn't go as deep with the two fingers but it got her going wild and she didn't object so I figured it didn't hurt. Then, I figured as I had gone quite deep before, and two fingers didn't seem to be a problem, I went quite deep with both. This led to her going "owowow" and me quickly pulling out. She said it was the same kind of pain as last time, only worse, and accompanied by a sharp pain which I thought could have been her hymen.

Can anybody shed some light on this please? Is it normal? Will it go away with more use? My fingers are only a few inches long, how can she possibly have sex?

How long were your fingernails? You could have scratched her. The female organs are amazing things. the vaginal canal will stretch to accomodatedifferent sizes of penises. I wouldn't worry too much about her ability to have intercourse.